Final answer:
The priority action for the nurse is to determine whether the patient is breathing spontaneously after extubating themselves.
Step-by-step explanation:
The priority action the nurse should take for the patient who extubated himself is to C) Determine whether the patient is breathing spontaneously.
When a patient extubates themselves, it means they have removed the breathing tube that was assisting their respiration. The nurse's first priority should be to assess the patient's ability to breathe independently. This involves closely monitoring the patient's breathing and oxygen saturation levels, as well as assessing for any signs of respiratory distress.
Applying a sterile dressing to the site (option A) or medicating the patient for pain and assessing for tissue damage (option D) may be necessary interventions, but they are not the priority action in this situation. Notifying the physician (option B) is important, but it should occur after the nurse has determined whether the patient is breathing spontaneously.